Scalloped Potatoes with Caramelized Onions

Ingredients

• 3 tablespoons salted Breakstone’s Butter
• 1 yellow onion, thinly sliced
• kosher salt
• black pepper
• 1/4 cup dry white wine
• 1 clove garlic, chopped or 1 cube frozen garlic
• 4 Yukon gold potatoes, peeled and sliced into 1/4-inch slices (about 2 pounds)
• 3 tablespoons salted Breakstones Butter
• 3 tablespoons all-purpose flour
• 1/2 teaspoon kosher salt
• 2 cups whole milk
• 1 and 1/2 cups shredded mozzarella cheese, plus more for topping
• salt, to taste
• pepper, to taste
• thyme, for garnish (optional)